一般焊缝机使用的空气压力不能低于()Mp。
A、0.5
B、0.3
C、0.4
D、0.7
参考答案:A
Twenty million years ago, Idoho was not the dry place as it is now. ______, it was warm and damp, covered with thick forests.
A.Thus
B.Besides
C.Rather
D.Otherwise
辐射集合管阀门泄漏,采取的措施错误的是()。
A、联系汇报
B、蒸汽掩护
C、泄漏较大停工处理
D、救火车保护继续生产